238 On the Erratic Phenomena of Scandinavia. 



causes act simultaneously at the present day. I have repre- 

 sented this phenomenon in all its details in Plate IX. of the 

 illustrations of my Etudes sur les Glaciers, There are here 

 two very distinct facts which are produced by two different 

 causes, that must not be confounded with each other, viz., the 

 hollowing out of the sinuous grooves occasioned by the cur- 

 rents of water which follow a serpentine course under the 

 glacier, and the hurinage of these grooved surfaces occasioned 

 by the gravel and the fragments of rock inserted in the sur- 

 face of the glacier, which moulds itself on its bed, and which 

 scratches by means of this emery, so to speak, as soon as it 

 advances, and that in consequence of the pressure exercised 

 by these masses on the base which supports them. 



" As to the assertion of M. Durocher, that glaciers only 

 abrade, polish, and scratch, by their lower surfaces, it is en- 

 tirely erroneous. The flanks of glaciers rub, abrade, polish, 

 and scratch, as well as their lower surfaces ; these flanks 

 carry, imbedded in the ice, just as considerable a quantity 

 of fragments of rock and of gravel as the unde. -surfaces 

 do ; and this rasping or grating agent, so to speak, acts 

 in the same manner on all the points where it is in con- 

 tact with the bottom and the flanks of the valleys containing 

 the glaciers. The localities where such recent polishings in 

 immediate contact with the glaciers which produced them are 

 the most distinct, are the glaciers of Rosenlaui, of the Aar, 

 of Viesch, of Zermatt, of Gauli, &c. 



" On the flanks of the glacier of Rosenlaui, it is the lime- 

 stone ; on those of the Aar and Viesch, it is the granite ; on 

 those of Gauli, it is the gneiss ; and on those of Zermatt, it 

 is the serpentine, which we find polished, grooved, and 

 scratched. Lastly, whether the cliff's which bound the gla- 

 ciers, and which are in immediate contact with them, be 

 more or less inclined, whether they be vertical, or whether 

 they overhang in such a manner as to form arches under 

 which the glacier gradually moulds itself as it advances, the 

 surface of the fixed rocks everywhere presents the same 

 polish, and the same hurinage as it does beneath the glacier. 

 Polished surfaces, more or less vertical, are to be observed 

 on the flanks of all the glaciers which I have cited ; on the 



